1. Field of the Invention
This invention relates to computer systems, specifically to computer-aided image processing, and more specifically to the merging of images to form a panoramic image.
2. Description of the Related Art
Image capture devices, such as cameras, may be used to capture an image of a section of a view or scene, such as a section of the front of a house. The section of the view or scene whose image is captured by a camera is known as the field of view of the camera. Adjusting a lens associated with a camera may increase the field of view. However, there is a limit beyond which the field of view of the camera cannot be increased without compromising the quality, or “resolution”, of the captured image. Further, some scenes or views may be too large to capture as one image with a given camera at any setting. Thus, it is sometimes necessary to capture an image of a view that is larger than can be captured within the field of view of a camera. In these instances, multiple overlapping images of segments of the view or scene may be taken, and then the images may be joined together, or “merged,” to form a composite image, known as a panoramic image.
Many computer programs and algorithms exist for automatically assembling a single panoramic image from multiple overlapping component images. Conventional computer programs for performing automatic panorama assembly generally concentrate on tools for automating the entire process, but operate under the assumption that the final output (the panoramic image) is the acceptable result, and that further manual or hand-modification is not needed.
While automated systems often do a good job in generating panoramic images, many situations, and demanding professional photographers and artists, may require exact control over how the images are blended together, their exposure and color balance settings, how the images overlap, and so on. Especially with automatic cameras or cameras set to automatic mode, the parameters or settings on a camera may differ between images, and thus two overlapping images of a scene may have different levels of exposure, color balance, brightness, contrast, hue and saturation, white and black points, and so on. In addition, artifacts may appear in one image that do not appear in an overlapping region of another image. Moving objects may also pose problems, as a moving object may not be in the same relative position in two overlapping images; for example, a moving object may appear in two different places in two overlapping images. In addition, aspects of a scene may not line up properly after an automatically generated alignment, generating misalignment artifacts. Control over the automatic panoramic image generation process may be manually achieved to correct for at least some of these problems or other problems using some image processing applications such as Adobe Photoshop®, but such control typically requires many tedious steps to achieve a desired result.
Further, conventional computer programs for automatically assembling a single panoramic image from multiple overlapping images typically generate the panoramic image as a single image element, with pixels in the actual image manipulated or modified to achieve the desired result, making further corrections to the final panoramic image difficult if not impossible.